Stage IV melanoma kills approximately 40,000 individuals per year globally. Early detection of new metastases is essential since up to three metastastic tumors can be resected for cure and patients with limited disease burden have improved clinical outcomes to immunotherapeutic agents such as ipilimumab (anti- CTLA4). As a result, full-body FDG-PET and CT imaging assessments are routinely conducted every three months for surveillance and every two months for response assessment. However, the utility of these scans is limited by both cost and the contribution of cumulative radiation exposure to secondary malignancies. The development of new non-invasive approaches for melanoma detection and frequent monitoring thus is expected to result in a marked reduction in melanoma-related deaths. The overarching goal of our research is the development of differential scanning calorimetry (DSC) analysis of blood plasma as a new, non- invasive diagnostic to enable more frequent monitoring and facilitate early detection of recurrences and early assessment of therapeutic response. Importantly, the University of Louisville's Melanoma Multi- Disciplinary Clinic and Tissue Repository has a large and growing collection of detailed de-identified clinical information and multiple longitudinal plasma specimens from stage I-IV melanoma patients (>3000 plasma samples and currently 219 resected melanoma metastases) which we propose to access in order to test this novel diagnostic approach. The application of DSC analysis to characterize the blood plasma proteome in our lab has provided an entirely new and complementary bioanalytical approach for the detection and monitoring of disease. DSC monitors heat changes associated with the thermal denaturation of biomolecules yielding a unique profile characteristic of the components, their amounts and interactions. Preliminary data indicate that direct analysis of small volumes of plasma using DSC yields profiles (or thermograms) that are sensitive to differences in the thermodynamic properties of abundant plasma proteins related to health status. DSC thermograms show sensitivity to disease pathology and therapeutic response and therefore could have considerable utility as a new diagnostic approach. The goals of this proposal are to examine the performance of DSC thermograms alongside standard PET/CT imaging for the diagnosis, the early detection of recurrence and the assessment of therapeutic efficacy in melanoma. If we are successful, the proposed research has the potential to contribute to earlier clinical assessment that can directly impact the care of melanoma patients. We propose three aims. Aim 1 addresses the utility of DSC thermograms for the detection and stage differentiation of melanoma compared with PET/CT. Aim 2 will determine the diagnostic performance of DSC analysis of longitudinal plasma samples to detect disease recurrence following surgical resection in stage III patients. In Aim 3, we will determine the utility of DSC for the assessment of early response to treatment in BRAF+ stage IV melanoma patients.